"Dirt Detectives"

For five days last week, 110 ATLAS collaborators worked in 10 different shifts to help clean and inspect the detector and the cavern that houses it before the toroid magnets are turned on. The whole endeavour is a delicate process as the collaborators wiped and vacuumed surfaces in all 16 phi sectors of the detector looking for any minuscule object that may have been left behind during the two years of upgrade and maintenance work. Here are glimpses from the cleaning project.

Images: Claudia Marcelloni

The cleaning crew comprised volunteers including physicists, engineers, and other support staff from all parts of the ATLAS experiment.

An ATLAS member vacuums the floor of Sector 13, which is at the very bottom of the 25m high ATLAS detector. The detector sits in a cavern 100m underground.The ATLAS detector has a 100 million active channels. The data passes from the detector to the electronics through the many cables which are colour-coded according to sub-detector type and functionality. The cables add to the challenge of the cleaning project.

Careful cleaning of the cavern is needed to ensure that there are no loose metallic objects around, which could move under ATLAS’ powerful magnetic field and damage the detector.

For safety reasons, everyone who works in the ATLAS cavern must wear a hard-hat, headlamps, antiskid steel-toed safety shoes, and a dosimeter.Some of the floor panels inside the detector were removed to access remote locations for thorough cleaning.The found objects, which included cable ties, bolts, washers, were collected in plastic bags and evacuated to the surface.

When the Large Hadron Collider is delivering particle collisions, the detector is sealed and no one is allowed to enter the cavern. During that time, only subatomic particles like muons and neutrinos would pass through these spaces.